The invention relates to an internal combustion engine for a motor vehicle having a cylinder head with coolant inlet and outlet ports and an engine block with coolant inlet and outlet ports and a coolant pump having an inlet in communication with the outlet ports of the cylinder head and the engine block and an outlet in communication with the inlet ports of the cylinder head and the engine block and also to a method of operating such an internal combustion engine.
Laid-open patent application DE 28 41 555 A1 discloses an internal combustion engine which has a coolant inflow for an engine block and a coolant inflow for a cylinder head. A pump feeds coolant to a temperature-controlled valve. Depending on the design, the valve feeds coolant into the cylinder head and/or the engine block. A continuous flow through the cylinder head and through the engine block cannot be established until the coolant has reached operating temperature. Since the cooling fluid in the engine block is not circulated until the operating temperature is reached it can heat up very quickly, as a result of which the frictional losses which occur after a cold start decrease quickly. The quantity of cooling fluid which flows via the cylinder head heats up very quickly as a result of the heat generated by the combustion taking place in the cylinder head so that the internal combustion engine reaches the operating temperature after a short time as a result of the proposed coolant supply arrangement.
It is the object of the present invention to further shorten a heating time of an internal combustion engine after a cold start in order to reduce fuel consumption and exhaust gas emissions.